Protection of vinylidene chloride polymers from the effects of light



Patented Aug. 15, 1950 PROTECTION OF VINYLIDENE CHLORIDE POLYMERS FROM THE EFFECTS OF LIGHT Thomas Houtman, Jr., Mi

to The Dow Chemical dland, Mich., assignor Company, Midland,

Mich., a corporation of Delaware No Drawing. Application October 30, 1946, Serial No. 706,797

Claims.

This invention relates "to compositions comprising polymeric vinylidene chloride or polymeric vinyl chloride products, and certain light stabilizers therefor.

It has become well recognized that polymers obtained by the polymerization of vinylidene chloride alone or with other polymerizable materials, including those in which the vinylidene chloride is a significant though minor constituent, are industrially valuable materials, but that such polymeric products, whether molded, ex-

7 been suggested for use as light stabilizers of polymers comprising significant amounts per cent or more) of vinylidene chloride. Of these, the 2,2dihydroxybenzophenone disclosed by Boyer et al. in U. 8. Patent No. 2,264,291 is among the most satisfactory, purely on the basis of protection afforded per unit weight of stabilizer, but thfs compound has the particular disadvantage of contributing a distinct yellow color to its compositions. This is objectionable in many fields of use of the polymers concerned. A similar problem exists with respect to vinyl chloride polymers.

It is accordingly among the objects -of the invention to. provide a composition comprising a polymer containing at least 10 per cent either of vinylidene chloride or vinyl chloride, stabilized againstthe darkening effects of exposure to light. A related object is to provide a composition comprising such a vinylidene chloride-containing polymer and certain new light stabilizers therefor.

It has now been found that the foregoing and related objects may be attained through the incorporation in a polymeric vinylidene chloride or vinyl chloride product (containing at least about 10 per cent of vinylidene chloride or of vinyl chloride) of certain substituted Z-hydroxy acylophenones having the genera1 formula taining from 1 to 4 carbon atoms, and Y is hydrogen when X is alkyl, and is a member of the group consisting of hydrogen and chlorine when X is chlorine.

These stabilizers may be incorporated with advantage in the polymer in amounts from about 0.5 to as much as 10 per cent of the weight of polymer. They have. no tendency to discolor the polymer products and serve to protect them from the darkening efiects of light. The present compounds may be added to the polymer in any of several ways, so long as reasonably uniform distribution of the stabilizer through the polymer is thereby obtained.

To illustrate the advantageous effects of the herein concerned stabilizers, it may be pointed out that an untreated film or filament of a polymer comprising significant amounts of vinylidene or vinyl chloride may assume a dark brown or black coloration on exposure to sunlight, and that similar films or filaments oi the treated composition resist discoloration under the same conditions of exposure for long periods of time.

The following example illustrates the practice 'of the present invention:

A powdered copolymer of about per cent vinylidene chloride and 15 per cent vinyl chloride, plasticized with 7 per cent of its weight of di-(alpha-phenylethyl) ether, was thoroughly mixed with 5 per cent of its weight of the indicated stabilizer, which had been dissolved in acetone. After mixing, the mass was dried and the resulting powder was molded to form discs 0.004 inch thick. These samples were exposed to Florida sunlight in an outdoor exposure test. The extent of darkening was determined by measuring the ability of each sample to transmit visible light before and after the outdoor exposure. A similar measurement was made on identical discs stored indoors in normal diffused light for 2 months. Other portions of the modified compositions were extruded as filaments of 0.020 inch diameter. These were wound on sample cards and exposed to Florida sunlight and tothe radiations in a standard fadeometer. These samples were ratecLon an arbitrary numerical basis, as follows:

Rating Description Comment Unchangedvery good Acceptable. Very slightly changedgood-- Do. Brownish tinge-fair. Usually acceptable. Dark brownbad Unacceptable. Black-very bad Do.

The results oi such tests with various of the herein concerned stabilizers are given in the fol- Table 1 Z-hydroxy 3.5-dichloro dodecanophenone Z-hydroxy 5-chloro tetradecanophenone 2-hydroxy 3,5-dlchloro tetradecanophenone Amount,

Per Cent Visible Light Transmitted Stabilizer Per Cent After 2 After 1 Months Month 1mm Diffused Florida Light Sunlight Nnnn 0 81 11 1 t 11 I g 31 1 a i 3 H o o-mcth ace 0 meme (1) W Y p 11 80.0 10.9 Do 0 80.8 0.0 h. 2 22-; 2'? -H dm BB-dlc roa t (2) 2 i) o 2 81.4 11.5 4 31.9 0.7 1 1 11 g 8'3 H b-choro r0 0 0110110..- 951.? --E i 4 19.0 7.9 o 0 80.0 6.7 (4) Z-Hydroxy 3,6-dlchloro proplophcnonn. 2-H (1:15 stainless1555511111.- 4 8010 (5) y "Y -1 4 111.1 10.1 (6) Z-Hydroxy 5 l1lorostenr0pl1cn0nc 3 56.9 4.1 Do 4 511.0 3.7 2-Hydroxy 3,5-dlcl1loro atcnroplmnono 6 I 60. 8, 9, 5 g; Z-IIydroxy 5-cl1loroucotoplwnonu 1 82.5 1.0 Do 5 81.7 71.4 11.3 (0) Z-Hydroxy b-mcthyl propiop 1 80.7 0.1 Do 6 80.3 70.5 as y lS-chloro butyropl 5 79.4 1,4 5 78.7 09.1 9.0 :1 00.2 Do. 3 01.7 55.7 6.0 s 82.5 0.0 in a 81.0 71. 9.2 3 Z-Hydrox methyl butymnhcnonm 5 77. Do 5 77.6 69.3 8.3 (14) Z-Hydroxy5-chlotooct1lll0Dhen0n0 4 80.7 71.1 9.6 Dn 5 70.6 72.1 7.5 Do 6 76 7 74.2 2.5 '(15) a-Hydroxy 3,5-dlchloro octanophenone 1 80.0 Dn 3 110.4 72.0 8.4 Do 4 80.5 74.8 5.7

Blushed.

Table 2 Compounds may also be used in which the various methyl, ethyl, propyl and butyl radicals re- Rating After Exposure place the chlorine in the 5-position in any of m. the compounds named.

hm Amount, Fsdeometer Florida Sunshine The data in the tables indicate that composi- (number Per cunt from tions conta1n1ng one per cent or more of the new Table 1) 100 200 1 a I 6 stabilizers show improvement over the untreated Mmths Mmths compositions, and that the presence of 3 per 50 cent or more of these stabilizers gives compo- 2 3 3 sitions of surprisingly high color stability when 6 s 3 a 3 exposed under the severe conditions of the tests. g g g f g 3 All of the new stabilizers are effective in the 0 1 2 2 1 1 a shorter tests, indicating general utility in comg g 4 g 3 3 positions for normal exposure to light, and most 0 2 3 4 2 3 g of them give adequate protection. in the extended 2 g 3 i g i 4 test to indicate utility in compositions which 0 2 a 4 g 3 4 may be given outdoor exposure to'direct sun- 3 3 3 light. No advantage is found in using over about 3 g g g g g 6 per cent of the stabilizers for their light pro- 4 2 3 4 3 3 tective effect, but, since they have plasticizing 6 2 3 4 3 3 action as well, larger amounts may be used if a 2 a 4 2 2 5 2 3 4 2 2 deslred. g g 3 4 g 4 The invention has been illustrated with respect 4 2 3 3 2 to the copolymer of vinylidene chloride and vinyl 5 2 3 3 1 2 chloride. It is equally applicable to each of the 5 3 s 4 2 8 3 2 s 4 2 :1 polymers contalnmg significant amounts, usually 2 g g i l g 10 per cent or more, of vinylidene chloride or of vinyl chloride, whether the other copolymerized ingredient is vinyl acetate vinyl butyrate, styrene, g zgfifisfig gg the same class Whlch glve acrylonitrile, ethyl acrylate or methyl methacryl- 1 I ate. or the like. The invention may be employed 2-hydroxy 5-chloro hexanophenone with molded and extruded forms of these poly- 2-hydroxy 3,5-dichl0ro hexanophenone mers and to protect solutions of the polymers 2-hydroxy 5-chloro dodecanophenone 7 and films deposited from such solutions.

I claim: 1

1. A composition of matter comprising a binary copolymer of vinylidene chloride and vinyl chloride which tends to darken on exposure to light, and, to protect the copolymer against the injurious' effects of light, from 0.5 to 10 per cent of a 2-hydroxy 3,5-dichloro acylophenone in which the acyl radical has from 2 to 18 carbon atoms, inclusive.

2. A composition of matter comprising a copolymer of about85, per cent vinylidene chloride, balance vinyl chloride, and, to protect the copolymer against the injurious 'efiects of light, from 0.5 to 10 per cent of a 2-hydroxy 3,5- dichloro acylophenone in which the acyl radical has from 2 to 18 carbon atoms, inclusive.

3. A composition of matter comprising a copolymer of about 85 per cent vinylidene chloride, balance vinyl chloride, and, to protect the copolymer against the injurious efiects of light, from 0.5 to. 10 per cent of 2-hydroxy 3,5-dichloro acetophenone.

4. A composition of matter comprising a cooctanophenone.

THOMAS HOUTMAN, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,136,333 Coleman Nov. 8, 1938 2,362,376 Heymann Nov. 7, 1944 2,364,027 Marshall Nov. 28, 1944 

1. A COMPOSITION OF MATTER COMPRISING A BINARY COPOLYMER OF VINYLIDENE CHLORIDE AND VNYL CHLORIDE WHICH TENDS TO DARKEN ON EXPOSURE TO LIGHT, AND, TO PROTECT THE COPOLYMER AGAINST THE INJURIOUS EFFECTS OF LIGHT, FROM 0.5 TO 10 PER CENT OF A 2-HYDROXY 3,5-DICHLORO ACYLOPHENONE IN WHICH THE ACYL RADICAL HAS FROM 2 TO 18 CARBON ATOMS, INCLUSIVE. 